Pouch film, method for manufacturing pouch film, and battery cell comprising same

Abstract

The pouch film according to the present invention may comprise: a base layer; a plurality of resin layers formed on the two respective surfaces of the base layer, with the base layer therebetween; and a fire-resistant coating layer coated on at least one resin layer among the plurality of resin layers.

Description

Pouch film and method for manufacturing pouch film, and battery cell including same

[0001] The present invention relates to a pouch film, a method for manufacturing the pouch film, and a battery cell including the same. More specifically, the present invention relates to a pouch film, a method for manufacturing the pouch film, and a battery cell including the same, which can enhance safety by improving fire resistance and enabling easy discharge of emitted substances such as venting gases. This application claims priority to Korean Patent Application No. 10-2023-0125883, filed on September 20, 2023, and all contents disclosed in the specification and drawings of the said application are incorporated by reference into the present application.

[0002] A semi-permanent battery that converts electrical energy into chemical energy and can be repeatedly charged and discharged is called a secondary battery, distinguishing it from a primary battery that cannot be reused after a single use.

[0003] Secondary batteries include lithium-ion batteries, nickel-cadmium (Ni-Cd), lead-acid batteries, nickel-metal hydride (Ni-MH), zinc-air batteries, and alkaline manganese batteries. Of these, lead-acid and lithium-ion batteries are the most widely commercialized. Lithium-ion batteries, in particular, offer advantages such as high energy storage density, lightweight and compact design, excellent safety, low discharge rates, and long lifespan, making them increasingly popular as batteries for electric vehicles.

[0004] Currently, the operating voltage of a single lithium-ion secondary battery cell is approximately 2.5 V to 4.5 V. Therefore, in order to apply secondary batteries as an energy source for electric vehicles, a battery module is formed by connecting multiple lithium-ion battery cells in series and / or parallel, and a battery pack is formed by connecting the battery modules in series and / or parallel.

[0005] These lithium ion secondary batteries are classified into cylindrical and prismatic batteries, in which the electrode assembly is housed in a cylindrical or prismatic metal can, depending on the shape of the battery case, and pouch-type batteries, in which the electrode assembly is housed in a pouch portion of an aluminum laminate sheet. Here, the pouch portion constitutes the outer material of the secondary battery, and is manufactured by forming a storage portion by pressing a flexible pouch film, and the electrode assembly is housed in the storage portion and the sides are sealed to manufacture the secondary battery.

[0006] Meanwhile, since secondary batteries involve chemical reactions during charging and discharging, their performance may deteriorate if they are used in environments higher than the appropriate temperature, and there is always a risk of unexpected fire or explosion if thermal control is not achieved at the appropriate temperature. Furthermore, since battery modules are structured to house these secondary batteries in a concentrated manner within the module housing, if any one of the secondary batteries experiences heat runaway and becomes a trigger cell, venting gas and flames will rapidly spread to surrounding secondary batteries (thermal propagation), making it easier for the secondary batteries to catch fire in a chain reaction. When a thermal event occurs, the venting gas and flames will come into direct contact with the pouch film.

[0007] Accordingly, there is a need for technology development for a layered pouch film with enhanced fire resistance that can delay as much as possible the heat transfer of flames generated from a trigger cell to adjacent secondary batteries when a thermal event occurs. Furthermore, if the layered pouch film structure facilitates the rapid and easy discharge of exhaust gases, such as venting gases, emitted from within the trigger cell, heat accumulation within the trigger cell and heat transfer to other cells can be minimized.

[0008] The present invention was created in consideration of the above problems, and the problem that the present invention seeks to solve is to provide a pouch film that can delay as much as possible the heat transfer of a flame generated from a trigger cell to another adjacent secondary battery when a thermal event occurs, while at the same time inducing rapid and easy discharge of exhaust gases such as venting gas discharged from inside the trigger cell, thereby minimizing heat accumulation and heat transfer to another cell, thereby improving the safety of the cell.

[0009] Another problem that the present invention seeks to solve is to provide a manufacturing method for manufacturing such a pouch film.

[0010] Another problem that the present invention seeks to solve is to provide a battery cell including such a pouch film.

[0011] The technical problems to be solved by the present invention are not limited to the problems described above, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.

[0012] A pouch film according to the present invention for solving the above problem may include: a base layer; a plurality of resin layers formed on one side and the other side of the base layer, with the base layer interposed therebetween; and a refractory coating layer formed by coating on at least one resin layer among the plurality of resin layers.

[0013] The above base layer, the plurality of resin layers, and the refractory coating layer are arranged to be laminated in a layered structure, and the refractory coating layer can be arranged on the outermost surface of the layered structure.

[0014] The plurality of resin layers include a first resin layer formed on the lower surface of the base layer based on the stacking direction of the layered structure; and a second resin layer formed on the upper surface of the base layer based on the stacking direction of the layered structure, and the refractory coating layer may be formed by coating the lower surface of the first resin layer and the upper surface of the second resin layer, respectively.

[0015] The above refractory coating layer can be formed by coating the entire area of ​​the lower surface of the first resin layer or the upper surface of the second resin layer.

[0016] The above pouch film is used for sealing the electrode assembly, and the refractory coating layer is formed by coating an area of ​​the lower surface of the first resin layer or the upper surface of the second resin layer, and an area where the refractory coating layer is not coated can form a discharge path for a discharged substance including a venting gas generated from the electrode assembly.

[0017] The above discharge path can be formed from a difference in coating thickness that occurs depending on whether the refractory coating layer is coated or not.

[0018] The above discharge path may be formed in a first direction on the plate surface of the first resin layer or the second resin layer, or may be formed in a second direction perpendicular to the first direction, or may be formed by partially mixing the first direction and the second direction.

[0019] The above refractory coating layer can be made of a ceramic material, an inorganic material, a MICA material, an aerogel, or a combination thereof.

[0020] The thickness of the above refractory coating layer may be 0.03 to 0.05 mm.

[0021] A method for manufacturing a pouch film according to the present invention for solving the above problem may include a step of applying a first resin layer to one surface of a base layer and laminating it; a step of applying a second resin layer to the other surface of the base layer and laminating it; and a step of coating a refractory coating layer on at least one of the first resin layer or the second resin layer.

[0022] The step of coating the above refractory coating layer can be performed to control the thickness by squeezing after applying the refractory material.

[0023] The above pouch film is used for sealing the electrode assembly, and in the step of coating the refractory coating layer, the refractory coating layer is formed by coating the entire surface area of ​​the first resin layer or the second resin layer, or by coating one surface area of ​​the first resin layer or the second resin layer, and the area where the refractory coating layer is not coated can form a discharge path for the ejected matter including the venting gas generated from the electrode assembly.

[0024] The area where the refractory coating layer is not coated can be formed by performing masking treatment along the discharge path on the first resin layer or the second resin layer, performing the squeezing, and then removing the masking.

[0025] In addition, a battery cell according to the present invention for solving the above problem comprises: an electrode assembly; and a pouch portion having a receiving portion for accommodating the electrode assembly. The pouch portion may be prepared by processing a pouch film having a refractory coating layer coated on at least one surface of a surface facing the electrode assembly or an opposite surface thereof.

[0026] The above pouch film is arranged to be laminated in a layered structure, and the refractory coating layer can be arranged on the outermost surface of the layered structure.

[0027] The above pouch film includes a base layer; and a plurality of resin layers formed on one side and the other side of the base layer, with the base layer interposed therebetween, and the refractory coating layer can be formed by coating on at least one resin layer among the plurality of resin layers.

[0028] The plurality of resin layers include a first resin layer formed on the lower surface of the base layer based on the stacking direction of the layered structure; and a second resin layer formed on the upper surface of the base layer based on the stacking direction of the layered structure, and the refractory coating layer can be formed by coating the lower surface of the first resin layer and the upper surface of the second resin layer.

[0029] Additionally, according to the present invention, a battery module including the above-described battery cell can be provided.

[0030] Here, the refractory coating layer is disposed on the outermost surface of the pouch film and is formed by coating one area, and an area where the refractory coating layer is not coated can form a discharge path for a discharged substance including a venting gas generated from the electrode assembly.

[0031] Additionally, according to the present invention, a vehicle including the above-described battery module can be provided.

[0032] According to one aspect of the present invention, a refractory coating layer is coated on the outermost surface of the pouch portion (the upper surface of the second resin layer of the pouch film) to enhance refractory properties, so that when a thermal event occurs, the heat transfer phenomenon of a flame generated from a trigger cell to another adjacent secondary battery can be delayed as much as possible.

[0033] In addition, according to one aspect of the present invention, the outermost surface of the pouch portion or the inner wall surface of the storage portion (the lower surface of the first resin layer of the pouch film) can be coated with a refractory coating layer, thereby inducing rapid and easy discharge of discharged substances such as venting gas discharged from within the trigger cell. Accordingly, heat accumulation in the trigger cell and heat transfer to other cells can be minimized, thereby improving the safety of the cell.

[0034] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0035] FIG. 1 is a schematic drawing of a battery cell including a pouch film according to one embodiment of the present invention.

[0036] Figure 2 is a cross-sectional view of the main components of Figure 1.

[0037] Figure 3 is a schematic cross-sectional view of a pouch film according to one embodiment of the present invention.

[0038] Figure 4 is a perspective view of a pouch film according to one embodiment of the present invention.

[0039] FIG. 5 is a photograph showing a flame test performed on a pouch film with a refractory coating layer coated on one side according to one embodiment of the present invention.

[0040] Figures 6 to 8 are drawings showing modified examples of Figure 4, in which various types of discharge paths are formed in the first resin layer.

[0041] Figure 9 is a schematic diagram of a squeezing process of a pouch film according to one embodiment of the present invention.

[0042] FIG. 10 is a drawing for explaining a vehicle according to one embodiment of the present invention.

[0043] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, it should be noted that the terms and words used in this specification and claims should not be construed as limited to their conventional or dictionary meanings. Based on the principle that the inventor can appropriately define the concepts of terms to best explain his or her invention, they should be interpreted in a way that conforms to the technical spirit of the present invention.

[0044] Therefore, it should be understood that the embodiments described in this specification and the configurations illustrated in the drawings are only some of the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention, and that there may be various equivalents and modified examples that can replace them at the time of filing this application.

[0045] In the drawings, the sizes of each component or specific parts of that component are exaggerated, omitted, or schematically illustrated for convenience and clarity of explanation. Therefore, the size of each component does not entirely reflect its actual size. If a detailed description of a related known function or configuration is deemed to unnecessarily obscure the gist of the present invention, such description will be omitted.

[0046]

[0047] FIG. 1 is a schematic drawing of a battery cell including a pouch film according to one embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view of the main components of FIG. 1.

[0048] Referring to FIGS. 1 and 2, a battery cell (3) according to the present invention may include an electrode assembly (10) and a pouch portion (100) having a storage portion (110) in which the electrode assembly (10) is accommodated.

[0049] The above electrode assembly (10) may have a plurality of positive electrodes (20) and a plurality of negative electrodes (30) alternately laminated with a separator (40) in between.

[0050] The positive electrode (20) may include a positive electrode active material coating layer (22) on at least one of the two surfaces of the positive electrode current collector (21). For example, the positive electrode (20) may include the positive electrode active material coating layer (22) on both surfaces of the positive electrode current collector (21). The negative electrode (30) may include a negative electrode active material coating layer (32) on at least one of the two surfaces of the negative electrode current collector (31). For example, the negative electrode (30) may include a negative electrode active material coating layer (32) on both surfaces of the negative electrode current collector (31). On one side of the positive electrode (20) and the negative electrode (30), electrode leads (20a, 30a) welded to electrode tabs may protrude. Although not shown in the drawing, the electrode leads (20a, 30a) may be connected to external electrical lines such as bus bars and terminals to be manufactured into a battery module or a battery pack. The above separator (40) can be interposed between the anode (20) and the cathode (30). The separator (40) is made of a porous material, insulates the anode (20) and the cathode (30), and provides a passage through which ions move.

[0051] These positive electrodes (20) and negative electrodes (30) can be alternately stacked vertically with a separator (40) interposed between them to form an electrode assembly (10), as shown in FIGS. 1 and 2. In addition, the electrode assembly (10) can be stored in the storage portion (110) of the pouch portion (100).

[0052] The above pouch portion (100) may be provided with a storage portion (110) in which the electrode assembly (10) is accommodated, as illustrated in FIG. 1. The pouch portion (100) may be formed by forming a pouch film (200) through press processing or the like, so that a storage portion (110), which is a predetermined space the size of the electrode assembly (10), is formed in the central region. The size of the storage portion (110) in the drawing is exaggerated for convenience of explanation.

[0053] The above storage portion (110) can be sealed. That is, the edge portions of the pouch film (200) positioned on the upper portion and the pouch film (200) positioned on the lower portion can be joined by mutual heat fusion, etc. Alternatively, an adhesive layer can be applied to the edge portion of each pouch film (200) to be joined.

[0054] As illustrated in Fig. 2, the space below the pouch film (200) positioned above corresponds to the inside of the pouch portion (100) and may be a portion facing the electrode assembly (10). The space above the pouch film (200) positioned above corresponds to the outside of the pouch portion (100) and may be a portion facing another adjacent battery cell (3).

[0055] FIG. 3 is a schematic cross-sectional view of a pouch film according to one embodiment of the present invention, which is an enlarged view of part A of FIG. 2, and FIG. 4 is a perspective view of a pouch film according to one embodiment of the present invention.

[0056] Referring to FIGS. 3 and 4, the pouch portion (100) may be prepared by processing a pouch film (200) having a refractory coating layer (300) coated on at least one surface of the surface facing the electrode assembly (10) or the other surface opposite the one surface. In addition, the pouch film (200) is used for sealing the electrode assembly.

[0057] That is, in FIG. 3, a refractory coating layer (300) is coated on the outermost upper surface of the pouch film (200), so that the refractory property can be enhanced. The fact that the refractory coating layer (300) is coated on the outermost outer surface of the pouch portion (100) means that flames from other external neighboring battery cells to the corresponding battery cell (3) can be blocked or delayed. That is, the outer surface of the storage portion (110) is surrounded by the refractory coating layer (300), and the refractory coating layer (300) can protect the electrode assembly (10) inside. Accordingly, when a flame generated from one trigger cell spreads to another secondary battery when a thermal event occurs, the refractory coating layer (300) on the outermost outer surface of the pouch portion (100) can block the flame, so that heat transfer can be delayed.

[0058] In addition, the inner wall surface of the storage unit (110) may also be coated with a refractory coating layer (300). That is, the refractory coating layer (300) may be coated on the outermost lower surface of the pouch film (200) of FIG. 3. In this case, the pouch film (200) of the pouch unit (100) can be prevented from ignition as much as possible from discharged substances such as venting gas discharged from inside the trigger cell, and rapid and easy discharge of the discharged substances can be induced. This will be described in detail later.

[0059]

[0060] Hereinafter, the pouch film (200) will be described in detail.

[0061] The above pouch film (200) may include a base layer (210), a plurality of resin layers (220), and a refractory coating layer (300) formed by coating on one of the plurality of resin layers (220).

[0062] Here, the components of the pouch film (200), that is, the base layer (210), the plurality of resin layers (220), and the refractory coating layer (300), may be arranged to be laminated in a layered structure. Specifically, the base layer (210) may be arranged between a pair of resin layers (220). And, based on FIG. 3, the refractory coating layer (300) may be arranged on the upper surface of any one of the resin layers (222) arranged above the base layer (210), and the refractory coating layer (300) may be arranged on the lower surface of any one of the plurality of resin layers (220) arranged below the base layer (210). That is, the refractory coating layer (300) may be arranged on the outermost upper surface and lower surface of the layered structure, respectively.

[0063] Specifically, the pouch film (200) according to the present embodiment may include a base layer (210).

[0064] The base layer (210) may be used as a barrier layer to prevent the penetration of oxygen or moisture from the outside. The base layer (210) may be made of any one material selected from aluminum or an aluminum alloy. For example, the base layer (210) may use a soft aluminum foil, and preferably, an aluminum foil containing iron may be used to provide formability to the aluminum foil. Alternatively, the base layer (210) may use an alloy in which various metals and non-metals are added to pure aluminum, or a stainless alloy. Here, the aluminum alloy may be an alloy including an element selected from the group consisting of silicon, boron, germanium, arsenic, antimony, copper, magnesium, manganese, zinc, lithium, iron, chromium, vanadium, titanium, bismuth, potassium, tin, lead, zirconium, nickel, cobalt, and combinations thereof.

[0065] The thickness of the above base layer (210) may preferably be 10 to 100 ㎛ in consideration of processability, moisture blocking ability, etc.

[0066] Meanwhile, the base layer (210) may be surface-treated to improve adhesion with the inner resin layer (220). The surface treatment may include etching, degreasing, anti-corrosion treatment, denaturation treatment, corrosion resistance treatment, etc. The surface treatment may be performed at each process during the processing of the pouch film (200) as needed or for functional reasons.

[0067] The pouch film (200) according to the present embodiment may include a plurality of resin layers (220) formed on one side and the other side of the base layer (210), with the base layer (210) interposed therebetween.

[0068] Here, the plurality of resin layers (220) may include a first resin layer (221) formed on one surface of the base layer (210) and a second resin layer (222) formed on the other surface of the base layer (210).

[0069] That is, the first resin layer (221) may be formed on the lower surface of the base layer (210) based on the stacking direction of the layered structure. The first resin layer (221) may be a layer that substantially faces the electrode assembly (10).

[0070] The first resin layer (221) may be made of a polyolefin-based (CPP) resin, a polyolefin ketone resin, an elastomer, or a combination thereof. In addition, the first resin layer (221) may also be made of a polybutylene-based resin, an ethylene copolymer, a propylene copolymer, a polyester-based resin, a polyamide-based resin, a polycarbonate-based resin, a fluorine-based resin, a silicone-based resin, or the like.

[0071] The thickness of the first resin layer (221) may preferably be 20 to 100 μm, and in the drawing, both the first resin layer (221) and the second resin layer (222) are depicted as having the same thickness as the base layer (210). The thickness of the first resin layer (221) may be selected differently in consideration of insulation and electrolyte resistance.

[0072] The second resin layer (222) may be formed on the upper surface of the base layer (210) based on the stacking direction of the layered structure. The second resin layer (222) may correspond to the outer surface of the pouch portion (100), and as a part that directly contacts a module case, etc., it is necessary to ensure insulation. Accordingly, the second resin layer (222) may be made of any one selected from polyamide, polyester, and nylon films, and in particular, the second resin layer (222) may be preferably made of nylon. The thickness of the second resin layer (222) may be 10 to 30 ㎛, and the thickness may be adjusted in consideration of insulation and formability.

[0073] An adhesive layer (230) may be interposed between the base layer (210) and each of the resin layers (220).

[0074]

[0075] Meanwhile, when a thermal event occurs, the venting gas and flame come into direct contact with the pouch film (200) that constitutes the outer material of the secondary battery, and if the pouch film (200) lacks fire resistance, there is a concern that the flame generated from the trigger cell may easily transfer heat to another adjacent secondary battery.

[0076] Accordingly, the pouch film (200) according to the present embodiment may include a refractory coating layer (300) formed by coating on the pair of resin layers (220).

[0077] The refractory coating layer (300) may be disposed on the outermost surface of the layered structure of the pouch film (200). That is, the refractory coating layer (300) may be formed by coating the lower surface of the first resin layer (221) and the upper surface of the second resin layer (222).

[0078] The above-mentioned refractory coating layer (300) can be manufactured from a ceramic material, an inorganic material, a MICA material, an aerogel, or a combination thereof, and any other material that has flame blocking performance and is fire-resistant and heat-resistant can be applied.

[0079] For example, the refractory coating layer (300) may be manufactured from a ceramic material. The refractory coating layer (300) may be coated by adding a portion of ceramic powder or the like to an organic material (e.g., fluororesin). The refractory coating layer (300) may be formed by applying a coating agent containing ceramic powder and curing at room temperature.

[0080] For example, the coating agent may be a slurry obtained by mixing ceramic fine powder such as alumina or silica with water, an inorganic dispersant, etc. It may also further include an inorganic oxide (K2O, BaO, etc.) that enables the formation of a glassy substance. In the present invention, such a slurry-type coating agent may be applied to the surface of the first resin layer (221) and / or the second resin layer (222) and cured to form a refractory coating layer (300). The application may be performed by any method such as dip coating, spin coating, spray coating, or brushing. Such a slurry-type coating agent can be directly coated on the first resin layer (221) and / or the second resin layer (222), and may have excellent corrosion resistance, wear resistance, and adhesion effects.

[0081] The above-described refractory coating layer (300) can block flames of 1000°C or higher. Accordingly, flame propagation to neighboring battery cells (3) or electrode assemblies (10) within the storage portion (110) can be blocked. That is, since the refractory coating layer (300) is coated on the upper surface of the second resin layer of the pouch film (200), the fire resistance can be enhanced, so that when a thermal event occurs, the heat transfer phenomenon of the flame generated from the trigger cell to other neighboring secondary batteries can be delayed as much as possible. When a battery module or battery pack including such a battery cell (3) is mounted on a vehicle, the heat propagation time between the battery cells (3) can be delayed, thereby ensuring the safety of the driver in an emergency. When a battery cell (3) within the battery module or battery pack ignites, the condition requiring a delay time can be satisfied so that the driver can evacuate before the flame is exposed to the outside of the battery module or battery pack. Therefore, the present invention can solve the increasing safety risk in battery modules and battery packs that require higher energy density of battery cells in a limited space for high energy concentration.

[0082] The thickness of the above-mentioned refractory coating layer (300) may be 0.03 to 0.05 mm (30 to 50 μm). The thickness may be selected while ensuring refractory performance and taking formability into consideration. The thickness of the above-mentioned refractory coating layer (300) is an example, and may be relatively thicker than the thicknesses of the first resin layer (221), the second resin layer (222), and the base layer (210).

[0083] According to the present embodiment, the pouch film (200) can be formed by coating the refractory coating layer (300) on the entire lower surface of the first resin layer (221), as mainly illustrated in FIG. 4. Accordingly, the lower surface of the first resin layer (221) of the pouch film (200) can be coated with the refractory coating layer (300), thereby delaying ignition of the pouch film (200) of the corresponding pouch portion (100) from discharged substances such as venting gas discharged from inside the trigger cell as much as possible. Accordingly, heat accumulation in the trigger cell and heat transfer to other cells can be minimized, thereby improving the safety of the cell.

[0084] However, the edge portion of the first resin layer (221) may not be coated with the refractory coating layer (300). This is because, when sealing the storage portion (110) in FIG. 1, bonding by heat fusion is facilitated. In addition, since a space for applying an adhesive layer needs to be provided, the edge portion of the first resin layer (221) may be free of the refractory coating layer (300).

[0085] FIG. 5 is a photograph showing a flame test performed on a pouch film with a refractory coating layer coated on one side according to one embodiment of the present invention.

[0086] The above-mentioned refractory coating layer (300) can be coated on the upper surface of the second resin layer (222). Referring to FIG. 5, the refractory coating layer (300) is coated on one surface of the pouch film (200) on the left side of the drawing (FIG. 5 (a)). In addition, the results of a flame test with a torch at a close distance (e.g., 15 cm) are shown. Referring to FIG. 5 (b), it is confirmed that the pouch film (200) is flame-resistant and that flame propagation is minimized, thereby confirming flame resistance. In FIG. 5 (c), the other surface of the pouch film (200) is not coated with the refractory coating layer (300), thereby confirming that there is no flame blocking ability or flame resistance.

[0087]

[0088] Meanwhile, a modified example of the above pouch film (200) will be described.

[0089] Figures 6 to 8 are drawings showing modified examples of Figure 4, in which various types of discharge paths are formed in the first resin layer.

[0090] Referring to FIGS. 6 to 8, the pouch film (200a) is formed by laminating a first resin layer (221) and a second resin layer (222) on the lower and upper surfaces, respectively, with the base layer (210) interposed therebetween, and the refractory coating layer (300, 300a) is coated on the lower surface of the first resin layer (221) and the upper surface of the second resin layer (222).

[0091] In particular, the refractory coating layer (300a) may be formed by coating on the lower surface of the first resin layer (221) or an area of ​​the upper surface of the second resin layer (222). Hereinafter, a discharge path (310a) described later may also be provided on the second resin layer (222), and for the convenience of explanation, an example in which the discharge path (310a) is formed on the first resin layer (221) will be mainly described. When the refractory coating layer (300a) is coated on an area of ​​the upper surface of the second resin layer (222), it may be possible to easily discharge discharged substances including venting gas generated outside the storage unit (110), i.e., outside the battery cell (3).

[0092] The lower surface of the first resin layer (221) may be partially coated with the refractory coating layer (300a). In addition, the area where the refractory coating layer (300a) is not coated may form a discharge path (310a) for the ejected matter including the venting gas generated from the electrode assembly (10). Accordingly, various types of discharge paths (310a) may be provided in the first resin layer (221) of the pouch film (200).

[0093] Specifically, referring mainly to FIG. 6, the refractory coating layer (300a) is formed along the first direction on the plate surface of the first resin layer (221), but sections where the refractory coating layer (300a) is not coated are generated at regular intervals. Accordingly, a discharge path (310a) in the first direction can be formed in the refractory coating layer (300a).

[0094] As another modified example, referring to FIG. 7, in the refractory coating layer (300b) of the pouch film (200b), a section where the refractory coating layer (300b) is not coated may be formed along the second direction on the plate surface of the first resin layer (221), and the discharge path (310b) may be formed in the second direction.

[0095] As another modified example, in the pouch film (200c) of FIG. 8, the discharge paths (311, 312) may be formed by partially mixing the first and second directions. That is, near one end of the pouch film (200), a refractory coating layer (300c) may be formed in a form in which the discharge paths (311, 312) in the first and second directions are mixed. In addition, the discharge path (311) in the first direction is exemplified in the central portion of the first resin layer (221).

[0096] In these variations, the discharge path (310a, 310b, 311, 312) can be formed from the difference in coating thickness (t, see FIG. 9) that occurs depending on the presence or absence of the refractory coating layer (300, 300a, 300b, 300c).

[0097] Accordingly, the lower surface of the first resin layer (221) of the pouch film (200, 200a, 200b, 200c) can be coated with a refractory coating layer (300, 300a, 300b, 300c), so that the pouch film (200, 200a, 200b, 200c) of the pouch section (100) can be delayed as much as possible from discharged substances such as venting gas discharged from inside the trigger cell.

[0098] In addition, it is possible to induce rapid and easy discharge of the discharged material. That is, the discharged material including the venting gas generated inside the storage unit (110) can easily move along the discharge path (310a, 310b, 311, 312) in the first or second direction, and can be quickly discharged to the edge of the battery cell (3) and discharged outside the battery cell (3). Accordingly, heat accumulation in the trigger cell and heat transfer to other cells can be minimized, thereby improving the safety of the cell.

[0099]

[0100] Hereinafter, the process of manufacturing the pouch film (200, 200a, 200b, 200c) according to the previous embodiment will be described.

[0101] Figure 9 is a schematic diagram of a squeezing process of a pouch film according to one embodiment of the present invention.

[0102] The process of arranging the layered structure of pouch films (200, 200a, 200b, 200c) is briefly described.

[0103] First, a step of applying a second resin layer (222) to the upper surface of the base layer (210) and bonding may be performed. The base layer (210) may be provided, and an adhesive layer (230) may be applied to the upper surface of the base layer (210). Then, the second resin layer (222) may be applied to the upper surface of the base layer (210) and bonded. Before or after this process, surface treatment of the base layer (210) may be performed in the middle.

[0104] Next, a step of applying and laminating a first resin layer (221) to the lower surface of the base layer (210) may be performed. An adhesive layer (230) may be interposed between the base layer (210) and the first resin layer (221). In addition, before laminating the first resin layer (221), surface treatment may be performed on the bonding surface with the base layer (210) to improve adhesion. Meanwhile, in the manufacturing process of the pouch film (200, 200a, 200b, 200c), the lamination order of the first resin layer (221) and the second resin layer (222) on the base layer (210) may be reversed, and the lamination process of the first resin layer (221) and the second resin layer (222) may be performed simultaneously.

[0105] Next, a step of coating a refractory coating layer (300) on at least one of the first resin layer (221) or the second resin layer (222) may be performed.

[0106] Referring to FIG. 9, in this embodiment, a process of coating a refractory coating layer (300) on both the first resin layer (221) and the second resin layer (222) is described. Specifically, the refractory coating layer (300) can be coated on both the lower surface of the first resin layer (221) and the upper surface of the second resin layer (222) with an initial coating thickness (D). In particular, the refractory coating layer (300') can be formed by coating the entire area of ​​the plate surface of the first resin layer (221). In addition, the step of coating the refractory coating layer (300') can perform thickness control by squeezing after applying a refractory material. That is, as illustrated in FIG. 9, a pouch film (200) with the refractory coating layer (300') applied thereto is inserted between rolls (50). Accordingly, after the squeezing process is performed and the refractory coating layer (300) is compressed, the coating thickness (t) is reduced to a preset thickness (0.03 to 0.05 mm). Here, the thickness of the refractory coating layer (300) is determined by the gap between the plurality of rolls (50), and the thickness, compression force, compression degree, etc. of the refractory coating layer (300) can be set differently by adjusting the gap.

[0107] Meanwhile, in the case of the above modified examples, masking treatment is required before the refractory coating layer (300a) coating operation. That is, in the step of coating the refractory coating layer (300a), the refractory coating layer (300a) is formed by coating an area of ​​the plate surface of the first resin layer (221), and an area where the refractory coating layer (300a) is not coated can form an ejection path (310a) for the ejected matter including the venting gas generated from the electrode assembly (10).

[0108] To this end, before coating the refractory coating layer on the lower surface of the first resin layer (221), masking treatment is performed. That is, the area where the refractory coating layer (300a) is not coated is masked along the discharge path (310a) on the first resin layer (221). In the case of Fig. 6, the lower surface of the first resin layer (221) is masked in the first direction. Then, the refractory coating layer (300a) is coated on the entire lower surface of the first resin layer (221). Then, after the squeezing is performed, the masking is removed so that the discharge path (310a) can be formed. Likewise, as shown in FIGS. 7 and 8, before coating the refractory coating layer (300b, 300c) on the lower surface of the first resin layer (221), the discharge path (310b, 310c, 311, 312) may be formed by performing masking treatment in the first direction or the second direction.

[0109] Meanwhile, it is preferable that the discharge paths (310a, 310b, 310c, 311, 312) are formed on a side other than the side on which the electrode leads (20a, 30a) in FIG. 1 are formed. For example, if the electrode leads (20a, 30a) of the electrode assembly (10) are formed on one side of the pouch film (200, 200a, 200b, 200c) in the first direction, they may be formed in a second direction or mixed with the first direction, but not on one side in the first direction. That is, the discharge paths (310a, 310b, 310c, 311, 312) are not arranged on the side where the electrode leads (20a, 30a) are arranged, so that the exposure of the electrode leads (20a, 30a) to discharged substances including venting gas can be minimized. Masking processing corresponding to the discharge paths (310a, 310b, 310c, 311, 312) can be performed. By performing these steps, a refractory coating layer (300, 300a, 300b, 300c) can be coated on the upper surface of the second resin layer (222) of the pouch film (200), so that the refractory property can be strengthened, so that when a thermal event occurs, the heat transfer phenomenon of the flame generated from the trigger cell to another adjacent secondary battery can be delayed as much as possible.

[0110] In addition, the lower surface of the first resin layer (221) of the pouch film (200) can be coated with a refractory coating layer (300, 300a, 300b, 300c), so that the pouch film (200) of the pouch portion (100) can be delayed as much as possible from discharged substances such as venting gas discharged from inside the trigger cell, and rapid and easy discharge of the discharged substances can be induced. Accordingly, heat accumulation in the trigger cell and heat transfer to other cells can be minimized, thereby improving the safety of the cell.

[0111]

[0112] The battery cell (3) according to the present invention includes the pouch film (200) according to the present invention as described above. The pouch portion (100) processed with the pouch film (200) may be provided with a storage portion (110) as shown in FIG. 1 to become an internal component of a pouch-shaped battery cell (3), or may be configured to store a cylindrical battery cell (3) if it is provided with a storage portion (110) having a shape corresponding to a jelly roll type.

[0113] Meanwhile, the battery module and battery pack (1, see FIG. 10) according to the present invention include the battery cell (3) according to the present invention as described above.

[0114] The battery module including the battery cell (3) described above can be applied to various devices. Representative examples of such devices include electric bicycles, electric vehicles, and hybrid vehicles, but the present invention is not limited thereto. A battery pack (1) including such a battery module is suitable for use as a battery pack (1) for an electric vehicle. It can also be used as an energy source for an energy storage system (ESS).

[0115] FIG. 10 is a drawing for explaining a vehicle according to one embodiment of the present invention.

[0116] Referring to Fig. 10, the battery pack (1) according to the present invention can be applied to a vehicle (V) such as an electric vehicle or a hybrid vehicle. That is, the vehicle (V) according to the present invention can include the battery pack (1) according to the present invention. The battery pack (1) can be installed in the body frame under the vehicle seat or in the trunk space, and when installed in the vehicle, the arrangement order of the battery pack (1) can be reversed as needed.

[0117] As described above, although the present invention has been described by limited embodiments and drawings, the present invention is not limited thereto, and various modifications and variations are possible by a person having ordinary skill in the art to which the present invention pertains within the scope of the technical idea of ​​the present invention and the equivalent scope of the patent claims to be described below.

[0118] Meanwhile, when terms indicating directions such as up, down, left, right, front, and back are used in this specification, it is obvious to those skilled in the art that these terms are only for convenience of explanation and may vary depending on the position of the target object or the position of the observer.

[0119] [Explanation of symbols]

[0120] 1: Battery pack 3: Battery cell

[0121] 10: Electrode assembly 20: Anode

[0122] 21: Cathode current collector 22: Cathode active material coating layer

[0123] 30: Cathode 31: Cathode current collector

[0124] 32: Negative active material coating layer 40: Separator

[0125] 50: Roll 100: Pouch

[0126] 110: Storage section 200, 200a, 200b, 200c: Pouch film

[0127] 210: Base layer 220: Resin layer

[0128] 221: First resin layer 222: Second resin layer

[0129] 230: Adhesive layer 300, 300a, 300b, 300c: Refractory coating layer

[0130] 310a, 310b, 311, 312: Discharge path

[0131] Coating thickness: t

Claims

1. Base layer; A plurality of resin layers formed on one side and the other side of the base layer, with the base layer interposed therebetween; and A pouch film characterized by comprising a refractory coating layer formed by coating on at least one resin layer among the plurality of resin layers.

2. In paragraph 1, The above base layer, the plurality of resin layers and the refractory coating layer are laminated in a layered structure, A pouch film characterized in that the refractory coating layer is arranged on the outermost surface of the layered structure.

3. In paragraph 2, The above plurality of resin layers are, A first resin layer formed on the lower surface of the base layer based on the stacking direction of the layered structure; and Based on the stacking direction of the layered structure, a second resin layer is formed on the upper surface of the base layer, A pouch film characterized in that the refractory coating layer is formed by coating the lower surface of the first resin layer and the upper surface of the second resin layer, respectively.

4. In paragraph 3, A pouch film characterized in that the refractory coating layer is formed by coating the entire area of ​​the lower surface of the first resin layer or the upper surface of the second resin layer.

5. In paragraph 3, The above pouch film is used for sealing the electrode assembly, The above refractory coating layer is formed by coating an area of ​​the lower surface of the first resin layer or the upper surface of the second resin layer, A pouch film characterized in that the area where the refractory coating layer is not coated forms a discharge path for the ejected matter including the venting gas generated from the electrode assembly.

6. In paragraph 5, A pouch film characterized in that the above discharge path is formed from a difference in coating thickness that occurs depending on whether the refractory coating layer is coated or not.

7. In paragraph 5, A pouch film characterized in that the discharge path is formed in a first direction on the plate surface of the first resin layer or the second resin layer, or is formed in a second direction perpendicular to the first direction, or is formed by partially mixing the first direction and the second direction.

8. In paragraph 1, A pouch film characterized in that the above refractory coating layer is made of a ceramic material, an inorganic material, a MICA material, an aerogel, or a combination thereof.

9. In paragraph 8, A pouch film, characterized in that the thickness of the refractory coating layer is 0.03 to 0.05 mm.

10. Step of applying a first resin layer to one side of the base layer and bonding it; A step of applying a second resin layer to the other surface of the base layer and bonding them together; and A method for manufacturing a pouch film, characterized in that it comprises a step of coating a refractory coating layer on at least one of the first resin layer or the second resin layer.

11. In paragraph 10, A method for manufacturing a pouch film, characterized in that the step of coating the above refractory coating layer comprises applying a refractory material and then squeezing it to adjust the thickness.

12. In paragraph 11, The above pouch film is used for sealing the electrode assembly, In the step of coating the above refractory coating layer, The refractory coating layer is formed by coating the entire surface area of ​​the first resin layer or the second resin layer, or by coating one surface area of ​​the first resin layer. A method for manufacturing a pouch film, characterized in that the area where the refractory coating layer is not coated forms a discharge path for the ejected matter including the venting gas generated from the electrode assembly.

13. In paragraph 12, A pouch film manufacturing method characterized in that the area where the refractory coating layer is not coated is formed by performing masking treatment along the discharge path on the first resin layer or the second resin layer, performing the squeezing, and then removing the masking.

14. Electrode assembly; and It includes a pouch portion having a storage portion in which the electrode assembly is accommodated. A battery cell characterized in that the pouch portion is processed into a pouch film having a refractory coating layer coated on at least one surface of the pouch portion facing the electrode assembly or the other surface opposite the one surface.

15. In paragraph 14, The above pouch film is arranged to be laminated in a layered structure, A battery cell characterized in that the refractory coating layer is arranged on the outermost surface of the layered structure.

16. In paragraph 15, The above pouch film, base layer; and It comprises a plurality of resin layers formed on one side and the other side of the base layer, with the base layer interposed therebetween, A battery cell characterized in that the refractory coating layer is formed by coating at least one resin layer among the plurality of resin layers.

17. In paragraph 16, The above plurality of resin layers are, A first resin layer formed on the lower surface of the base layer based on the stacking direction of the layered structure; and Based on the stacking direction of the layered structure, a second resin layer is formed on the upper surface of the base layer, A battery cell characterized in that the refractory coating layer is formed by coating the lower surface of the first resin layer and the upper surface of the second resin layer.

18. A battery module comprising a battery cell according to any one of claims 14 to 17.

19. In paragraph 18, A battery module characterized in that the refractory coating layer is disposed on the outermost surface of the pouch film and is formed by coating one area, and the area where the refractory coating layer is not coated forms a discharge path for ejected matter including venting gas generated from the electrode assembly.

20. A vehicle characterized by including a battery module according to Article 18.

Images